1. Field of Invention
This invention pertains to portable devices for lifting a vehicle wheel. More particularly, this invention pertains to portable devices for lifting wheels of lowered vehicles.
2. Description of the Related Art
Portable ramp devices utilized for lifting one or more vehicle wheels off of a ground surface are available to facilitate changing a tire, for adjusting the vehicle suspension system, and to allow maintenance activities or inspection activities underneath the vehicle. Prior art portable ramp devices generally require at least about seven to eight inches clearance between the ground and the vehicle side frame, front bumper or rear bumper, depending on the preferred positioning for the ramp device. Due to the height above the ground of prior portable ramp devices, each ramp device is difficult to use for lifting modified vehicles having ground clearance heights reduced to between about three inches to about six inches due to suspension modifications and/or addition of front and rear bumper assemblies extending low to the ground surface, as is typical of modified “low aspect” or “street rod” vehicles. Typically for lowered cars or trucks having side aerodynamic fenders attached, one short two inch high jack device is initially used to initially lift the underside of the lowered car or truck, such as a scissor-extending jack, and a second jack having a six inch to eight inch height is utilized for further vehicle lift.
A prior art wheel ramp device is disclosed in U.S. Pat. No. 4,920,596, issued May 1, 1990, and includes a two level ramp device composed of a first ramp segment attachable at a rear portion to a second ramp segment providing a first support level, which is attachable at a rear portion to a third ramp having a second support level for positioning a car wheel thereon. The ramps have side legs connected by side rails, and each ramp is attachable end-to-end with pairs of end brackets extended backwards to cradle the trailing ramp between the end brackets. The design of the first and second ramps requires alignment end-to-end and assembly of the units by positioning each axially before connection to the respective pairs of end brackets. If a car wheel is driven onto the first ramp without the second and third ramps portion attached, the first ramp can “kick-out” or slide away from the wheel due to the limited bottom surface area provided by the side legs contacting against the ground surface. Use of this type of ramp device requires assembly before a car wheel progresses to an elevated height to allow aligning of each rear portion of second and third ramps when unweighted to protect the user from “kick-out” by the ramp device. Further, this type of ramp device requires end-to-end alignment for proper cradling by the end brackets extended from each rear portion of each ramp segment, thereby posing an unsafe situation if the operator attempted to assemble the aligned ramp segments while a front or rear wheel is on a first ramp segment and is partially elevated above a ground surface.
A leveling ramp device for a vehicle tire is disclosed in U.S. Pat. No. 4,427,179, issued Jan. 24, 2984, and includes a plurality of planar planks that are stacked with front ends forming a stairway for a wheel to climb, and having rear ends enclosed by a back frame having side members enclosing side wall portions of each stacked plank. Each ramp plank is further held in place by a downwardly projecting dowel which is inserted in the top surface of the next lower ramp plank to maintain alignment of the front portions of the stacked ramp planks. The plurality of ramp planks must be aligned, stacked and enclosed by the back frame before a vehicle tire is moved up the front end surfaces, otherwise the planks will be pushed sideways or backwards without the back frame and interlocking dowels in place. A vehicle tire can not be positioned in a partially elevated horizontal position other than on an uppermost surface, and additional ramp planks must be added before the tire is initially positioned at the uppermost height.
An elevating and leveling ramp device for a vehicle wheel is disclosed in U.S. Pat. No. 3,752,441, and includes a plurality of hollow blocks forming step-like sections that are nestable within the next larger hollow block. The elevating and leveling ramp device allows for extension of each hollow block from the next larger block to form a series of steps on which a vehicle wheel is moved. During accordion-like extension of respective hollow blocks from the next larger hollow block, the respective blocks are aligned and connected end-to-end, but are not laterally movable for disassembly while the vehicle wheel is positioned on any of the blocks. Therefore, any larger hollow blocks must be added to the ramp device before a vehicle wheel is moved on a low height block or on a middle height block.
There exists a need for a portable modular wheel lift which provides a laterally assembled combination of modular units for incrementally lifting a wheel of a vehicle having minimal ground clearance. There is a further need for a method for assembly and operation of a modular wheel lift system for elevating one or more wheels of a vehicle having minimal ground clearance.